It is known to activate a wireless data terminal by connecting a mobile terminal such as a notebook computer or personal data device to a specialized data unit such as a mobile modem. The mobile modem has associated wireless mobile telephone capabilities or a separate mobile phone to which it is connected and acts as a mobile data unit. A uniquely identified communication link between a land-based based terminal such as a desktop computer connected with a hard-wired data unit such as a modem and the mobile data unit can be made by using the mobile identification number (“MIN”) of the mobile modem. Thus, the current art requires one hard-wired modem and one hard-wired telephone circuit per land-based terminal.
In a hard-wired telephone network a specific telephone number is associated with only one serving switch, located at a specific geographic location. In a wireless network a specific mobile number for a mobile data unit may be served by any single one of a vast number of available switches depending on the specific geographic location of the mobile data unit at the time a call is made. Such portability of use is one of the basic hallmarks of wireless telephony.
In the present implementation of wireless networks, each mobile number is associated by both the wireless and hard-wired networks with a specific geographic home switch location. The home switch location includes a physical connectivity matrix and a stored program control section that houses the logic and algorithms necessary to control the connectivity. Associated with wireless switches is a collection of Radio Frequency (RF) channels, aggregated in multiple physical locations called cell sites across a specific area corresponding to a serving market and variously known in the United States by the acronyms MSA, RSA, MTA, and BTA, depending on the FCC license A pair of entities known as the Home Location Register (“HLR”) and Visited Location Register (“VLR”) have been defined by the American National Standards Institute ANSI-41 standard, together with a set of protocols for communication between switches, which allows seamless roaming, or call delivery, to be made. In the present art, the VLR is associated with the wireless switch where a mobile unit is currently being served, and the HLR is associated with the switch where the mobile unit phone number “resides” (the geographic location where all hard-wired originated call will be directed before being routed to a wireless switch with which the mobile unit is in communication).
Typically, when the VLR and HLR are physically in the same location, the mobile unit is “Home” and is not roaming. When the VLR and the HLR are not in the same location and specialized protocols are not implemented to make the mobile phone act as if it were “home”, then the mobile unit is “roaming”.
Phone calls from a land-based terminal to a mobile terminal can be completed while roaming only by a carefully orchestrated set of interactions between the HLR and VLR, all of which are described and defined by ANSI-41. ANSI-41 defines the HLR as a logically and possibly physically separate device from the actual switching matrix underlying the RF portion of the wireless network for the home location of the mobile unit. Similarly, the VLR is defined as a logically and possibly physically separate device from the actual switching matrix underlying the RF portion of the wireless network from which a mobile unit is currently being served. This physical separation, together with the Signaling System Seven (SS7) and the associated messages and protocols are existing underlying components utilized by the invention.
The mobile numbers associated with the mobile data unit are ones for which no physical geographic location have been assigned. They may be standard numbering plan numbers or non-standard (not normally dialable) numbers. The numbers will be placed in a HLR database by which they can be interacted with from the current VLR location by a mobile phone. Since the HLR used by this invention has no associated switching matrix, all mobile stations are always in a roaming state active (since the HLR and VLR cannot coexist).
A mobile unit makes its presence known, either by Power-on Registration, Autonomous Registration, a Call Attempt or any other means.
For the purpose of illustration, in the existing art, a call placed from a hard-wired land-based terminal to a mobile terminal is routed from the serving hard-wired switch to the HLR for the mobile unit associated with the mobile terminal using the public switch telephone network (“PSTN”), possibly by way of additional local or inter-exchange carrier (“IXC”) switches.
The HLR interacts with the VLR to obtain a temporary local directory number (“TLDN”) from the allocations made for the physical location of the serving switch connected to the mobile unit. The switch containing the HLR then again routes the call by way of the public switch telephone network to the switch containing the VLR, which then establishes the necessary wireless RF connection to the mobile unit. Thus, two separate public switched network connections are required to complete a single Land-to-Mobile call while roaming.,
FIG. 1 illustrates the current state of the call delivery method for a land-based hard-wired originated call in more detail. In this figure, a land-based terminal 3 is connected to a hard-wired data unit 5 such as a modem, which is in turn connected by a wire 7 to an end office switch 9. Switch 9 originates a call to a mobile terminal 11 such as a notebook computer to a mobile modem or a mobile modem/phone combination acting as a mobile data unit 13. The end office 9, using predefined algorithms and data routes the call to the public switch telephone network/inter-exchange carrier switches (“PSTN/IXC”) 15 over existing connectivity 17. The PSTN/IXC 15 routes the call to the home cellular switch 19, the geographic home of the number associated with mobile unit 13, by way of existing connectivity 18. The home cellular switch 19 sends a routing request to the home location register 23, which consults its internal database and determines the last known location of the mobile station 11 in a particular visited location register (VLR) 25. VLR 25 is one of multiple possible such registers.
HLR 23 sends a routing request 27 to VLR 25, possibly routed by way of one or more signal transfer points (“STP”) 29. The VLR 25 determines that the call is deliverable and allocates a temporary local directory number (TLDN) from a pool of numbers whose geographic base is the serving switch 31. The TLDN is returned using existing connectivity 30 to the HLR 23, again possibly routed by way of one or more regional transfer points 29. The HLR 23 then forwards the TLDN to the home mobile switch 19 in the response to the routing request by route 35.
The home mobile switch 19 passes the TLDN on to a second PSTN/IXC 37 for delivery to the serving switch 31 associated with the VLR 25 where the mobile unit 13 is located. The serving switch 31 sends a routing request 39 to VLR 25. The VLR 25 associates the TLDN previously allocated with the mobile data unit 13 and passes the information back to serving switch 31 using response route 41. Serving switch 31 is now able to connect the incoming call to the mobile unit 13 and mobile terminal 11 by way of the correct cell site 42. The mobile unit 13 and mobile terminal 11 can now communicate with land-based terminal 3 through hard-wired data unit 13.
It should be noted in FIG. 1 that two separate PSTN/IXC connections are required for call delivery.